Pregnant women with a documented psychiatric
disorder or substance abuse problem have a significantly elevated
risk of having poor birth outcomes, according to results of a
population-based study conducted in California.1 Among
infants born there in 1995, those whose mothers had a diagnosed
psychiatric or substance-related disorder had roughly 2-4 times the
odds of other babies of having a low or very low birth weight, and
of being delivered preterm. As the analysts observe, the findings
are important because psychiatric disorders are not uncommon among
pregnant women, and earlier studies of their relationship to poor
birth outcomes have examined symptoms or stress rather than
documented diagnoses.

Using a data set that links statewide birth and
infant death records with maternal and infant hospital discharge
records, the analysts gathered information on more than 521,000
women who delivered in 1995 and on their liveborn, singleton
infants. Data included women's demographic characteristics, use of
prenatal care, birth outcomes, and diagnoses of psychiatric
disorders (for example, mood, psychotic, eating, sleep, sexual or
gender identity, and adjustment disorders) and substance-related
disorders.

In all, fewer than 3% of women had a documented
diagnosis--0.4% had a psychiatric diagnosis, 1.0% a diagnosis of
substance abuse and 1.4% both. Those with any documented disorder
were more likely than those with none to be black or white, to be
covered by Medi-Cal (California's Medicaid program), to be single,
to have had more than three prior deliveries and to have received
inadequate prenatal care (as measured by a standard index). The
vast majority of women with a diagnosis (92%) had their condition
identified at the time they were hospitalized for delivery; 14%
received their diagnosis while pregnant, and 6% had a disorder
diagnosed both prenatally and at delivery.

Some 15-21% of women with a diagnosis delivered
before 37 weeks' gestation (preterm), compared with 9% of those
with no diagnosis. Similarly, whereas 5% of women with no diagnosis
bore an infant who was low-birth-weight (less than 2,500 g), the
proportion was 10-18% among those with a diagnosis; for very low
birth weight (less than 1,500 g), the proportion was 1% for those
with no documented disorder and 3% for women with a psychiatric or
substance-related disorder or both.

The analysts used logistic regression to examine
the risk of poor outcomes while controlling for the effects of
marital status, ethnicity and adequacy of prenatal care. These
calculations revealed that compared with women who had no
diagnosis, those with a psychiatric disorder had twice the odds of
bearing a low-birth-weight infant (odds ratio, 2.0), those with a
substance-related disorder had almost four times the odds (3.7) and
those with both types of diagnoses had three times the odds (3.0).
Each category of diagnosis was associated with about a tripling of
the risk of very low birth weight: Odds ratios were 2.8-3.0. Women
with a psychiatric disorder had a 60% greater risk of preterm
delivery than those with no documented disorder (odds ratio, 1.6),
while women with substance-related or dual diagnoses had roughly
doubled risks (2.4 and 2.3, respectively).

Additional analyses--one including a larger number
of potentially confounding variables and one that was restricted to
women who had not given birth before, to control for the possible
confounding effect of a history of preterm delivery--produced
essentially similar results. When the analyses were limited to
women whose diagnoses had been made before delivery, the findings
remained unchanged.

The analysts comment that the findings "underscore
the importance of improved detection of psychiatric and substance
use disorders" among pregnant women. Once such disorders are
identified, they point out, "increased monitoring...could enhance
timely interventions and improve birth outcomes." --D.
Hollander